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| United States Patent |
6,034,039
|
|
Gomes
, et al.
|
March 7, 2000
|
Lubricating oil compositions
Abstract
Complex detergents provide improved deposit control and corrosion
protection in crankcase lubricants.
| Inventors:
|
Gomes; Jose Manuel Gaspar (Oxfordshire, GB);
Skinner; Philip (Oxfordshire, GB)
|
| Assignee:
|
Exxon Chemical Patents, Inc. (Linden, NJ)
|
| Appl. No.:
|
200096 |
| Filed:
|
November 25, 1998 |
Foreign Application Priority Data
| Nov 28, 1997[GB] | 9725353 |
| Dec 02, 1997[GB] | 9725534 |
| Current U.S. Class: |
508/331; 508/332; 508/360; 508/398; 508/574; 508/583 |
| Intern'l Class: |
C10M 159/22; C10M 159/24; C10M 163/00 |
| Field of Search: |
508/398,331,332,360,574,583
|
References Cited
U.S. Patent Documents
| 2719125 | Sep., 1955 | Roberts.
| |
| 2719126 | Sep., 1955 | Fields et al.
| |
| 3087932 | Apr., 1963 | Little, Jr.
| |
| 4283294 | Aug., 1981 | Clarke | 508/360.
|
| 5256322 | Oct., 1993 | Cohu | 508/398.
|
| 5330665 | Jul., 1994 | Cane et al. | 508/574.
|
| 5433871 | Jul., 1995 | O'Connor et al. | 508/331.
|
| 5674821 | Oct., 1997 | Cook et al. | 508/574.
|
| 5804537 | Sep., 1998 | Boffa et al. | 508/398.
|
| Foreign Patent Documents |
| 024156 | Feb., 1981 | EP.
| |
| 312 312 A1 | Apr., 1989 | EP.
| |
| 317 348 A1 | May., 1989 | EP.
| |
| 347 103 A1 | Dec., 1989 | EP.
| |
| 208560 | Dec., 1997 | EP.
| |
| 97/46646 | Dec., 1997 | WO.
| |
| 97/46647 | Dec., 1997 | WO.
| |
| 97/46645 | Dec., 1997 | WO.
| |
| 97/46644 | Dec., 1997 | WO.
| |
| 97/46643 | Dec., 1997 | WO.
| |
Other References
Amos, R. and Albaugh, E.W. in "Chromatography in Petroleum Analysis",
Altgelt, K.H. and Gouw, T.H., Eds, pp. 417 to 422, Marcel Dekker, Inc.,
New York and Basel, 1979.
Epton in Trans. Far. Soc. Apr. 1948, 226.
|
Primary Examiner: Howard; Jacqueline V.
Attorney, Agent or Firm: Ohlandt, Greeley, Ruggiero & Perle
Claims
What is claimed is:
1. A lubricating oil composition comprising a mixture of at least two
metal-containing detergents, a first, detergent (a), being a metal
phenate, sulphonate, salicylate, naphthenate, or carboxylate, and a
second, detergent (b), being a calcium overbased detergent comprising a
surfactant system derived from at least two surfactants, at least one of
which is a sulphurized or non-sulphurized phenol and the other, or at
least one other, of which is a surfactant other than a phenol surfactant,
the proportion of the said phenol in the surfactant system being at least
45 mass %, and the overbased detergent having a TBN: surfactant ratio of
at least 14.
2. A lubricating oil composition comprising a mixture of at least two
metal-containing detergents, a first, detergent (a), being a metal
phenate, sulphonate, salicylate, naphthenate, or carboxylate, and a
second, detergent (b), being a calcium overbased detergent comprising a
surfactant system derived from at least two surfactants, at least one of
which is sulphurized or non-sulphurized, salicylic acid and the other, or
at least one other, of which is a surfactant other than a salicylic
surfactant, the proportion of the said salicylic acid in the surfactant
system being at least 25 mass %, and the overbased detergent having a
TBN:% surfactant ratio of at least 16.
3. A lubricating oil composition comprising a mixture of at least two
metal-containing detergents, a first, detergent (a), being a metal
phenate, sulphonate, salicylate, naphthenate, or carboxylate, and a
second, detergent (b), being a calcium overbased detergent comprising a
surfactant system derived from at least three surfactants, at least one of
the surfactants being a sulphurized or non-sulphurized phenol, for a
derivative thereon, at least one other of the surfactants being a
sulphurized or non-sulphurized salicylic acid or a derivative thereof, the
third, or a third, surfactant being a surfactant other than a phenol or
salicylic surfactant, the proportion of the said phenol in the surfactant
system being at least 35 mass %, and the overbased detergent having a
TBN:% surfactant ratio of at least 11.
4. A lubricating oil composition comprising a mixture of at least two
metal-containing detergents, a first, detergent (a), being a metal
phenate, sulphonate, salicylate, naphthenate, or carboxylate, and a
second, detergent (b), being a calcium overbased detergent comprising a
surfactant system derived from at least two surfactants other than (c) an
acid of the formula R.sup.a --CH(R.sup.b)--COOH, wherein R.sup.a
represents an alkyl or aIkenyl group containing 10 to 24 carbon atoms and
R.sup.b represents hydrogen, an alkyl group with 1 to 4 carbon atoms, or a
CH.sub.2 COOH group, or an acid anhydride, acid chloride. or ester
thereof, and (d) a di- or polycarboxylic acid containing from 36 to 100
carbon atoms or an acid anhydride, acid chloride or ester thereof, at
least one of the surfactants being a sulphurized or non-sulphurized phenol
and the other, or at least one other, of the surfactants being a
surfactant other than a phenol surfactant, the proportion of the said
phenol in the surfactant system being at least 35 mass %, and the
overbased detergent having a TBN:% surfactant ratio of at least 15.
5. A lubricating oil composition comprising a mixture of at least two
metal-containing detergents, a first, detergent (a), being a metal
phenate, sulphonate, salicylate, naphthenate, or carboxylate, and a
second, detergent (b), being a calcium overbased detergent comprising a
surfactant system derived from at least two surfactants other than (c) an
acid of the formula R.sup.a --CH(R.sup.b)--COOH, wherein R.sup.a
represents an ally or alkenyl group containing 10 to 24 carbon atoms and
R.sup.b represents hydrogen, an alkyl group with 1 to 4 carbon atoms, or a
CH.sub.2 COOH group, or an acid anhydride, acid chloride or ester thereof,
and (d) a di- or polycarboxylic acid containing from 36 to 100 carbon
atoms or an acid anhydride, acid chloride or ester thereof, at least one
of the surfactants being a sulphurized or non-sulphurized salicylic acid
and the other, or at least one other, of the surfactants being a
surfactant other than a salicylic surfactant, the proportion of the said
salicylic acid in the surfactant system being at least 10 mass %, and the
overbased detergent having a TBN:% surfactant ratio of at least 11.
6. A lubricating oil composition comprising a mixture of at least two
metal-containing detergents, a first, detergent (a), being a metal
phenate, sulphonate, salicylate, naphthenate, or carboxylate, and a
second, detergent (b), being a calcium overbased detergent comprising a
surfactant system derived from at least two surfactants, at least one of
the surfactants being a sulphurized or non-sulphurized phenol and the
other, or at least one other, of the surfactants being a sulphurized or
non-sulphurized salicylic acid, the total proportion of the said phenol
and the said salicylic acid in the surfactant system being at least 55
mass %, and the overbased detergent having a TBN:% surfactant ratio of at
least 11.
7. A lubricating oil composition comprising a mixture of at least two
metal-containing detergents, a first, detergent (a), being a metal
phenate, sulphonate, salicylate, naphthenate, or carboxylate, and a
second, detergent (b), being a calcium overbased detergent comprising a
surfactant system derived from at least two surfactants, at least one of
which is a sulphurized or non-sulphurized phenol and the other, or at
least one other, of which is a surfactant other than a phenol surfactant,
the proportion of the said phenol in the surfactant system being at least
15 mass %, and the overbased detergent having a TBN:% surfactant ratio of
at least 21.
8. A composition as claimed in claim 1, wherein at least one of the
surfactants from which component (b) is derived is an alkyl, substituted
phenol.
9. A composition as claimed in claim 1, wherein at least one of the
surfactants from which detergent (b) is derived is a sulphonic acid or
derivative thereof.
10. A composition as claimed in claim 9, wherein the sulphonic acid is an
alkyl, substituted aryl sulphonic acid.
11. A composition as claimed in claim 1, wherein detergent (a) is a calcium
containing overbased detergent.
12. A composition as claimed in claim 11, wherein detergent (a) is a
phenate or sulphonate.
13. A composition as claimed in claim 12, wherein detergent (a) is a
calcium sulphonate of TBN of at least 50.
14. A composition as claimed in claim 12, wherein detergent (a) comprises a
calcium phenate of TBN at most 160.
15. A composition as claimed in claim 12, wherein detergent (a) comprises a
calcium sulphonate of TBN at most 50.
16. A composition as claimed in claim 1, wherein detergent (a) and
detergent (b) are present in a mass ratio of from 1:5 to 5:1,
advantageously from 1:3 to 3:1, preferably from 2:3 to 3:2.
17. A composition as claimed in claim 1, wherein detergents (a) and (b) are
present in a total proportion of from 0.25 to 3, mass per cent, based on
the total mass of the lubricating oil composition.
18. An additive concentrate comprising detergents (a) and (b) as defined in
any one of claims 1 to 7 in an oil, or a solvent or dispersant miscible
with oil, the total proportion of detergent in the concentrate being from
2.5 to 90 mass %.
19. A composition as claimed in any one of claims 1 to 7 that is
substantially magnesium-free.
20. A method to provide corrosion protection or deposit control at a lower
TBN or greater protection or control at the same TBN of a crankcase
lubricating oil containing a detergent which is a metal phenate,
sulphonate, salicylate, naphthenate or carboxylate, the method comprising
providing in the crankcase lubricating oil a second detergent which is
selected from:
(1) a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants, at least one of which is a sulphurized or
non-sulphurized phenol; and the other, or at least one other, of which is
a surfactant other than a phenol surfactant, the proportion of the said
phenol in the surfactant system being at least 45 mass %, and the
overbased detergent having a TBN:% surfactant ratio of at least 14;
(2) a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants, at least one of which is sulphurized or
non-sulphurized salicylic acid and the other, or at least one other, of
which is a surfactant other than a salicylic surfactant, the proportion of
the said salicylic acid in the surfactant system being at least 25 mass %,
and the overbased detergent having a TBN:% surfactant ratio of at least
16;
(3) a calcium overbased detergent comprising a surfactant system derived
from at least three surfactants, at least one of the surfactants being a
sulphurized or non-sulphurized phenol, at least one other of the
surfactants being a sulphurized or non-sulphurized salicylic acid, the
third, or a third, surfactant being a surfactant other, than a phenol or
salicylic surfactant, the proportion of the said phenol in the surfactant
system being at least 35 mass %, and the overbased detergent having a
TBN:% surfactant ratio of at least 11;
(4) a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants other than (c) an acid of the formula
R.sup.a --CH(R.sup.b)--COCOH, wherein R.sup.a represents an alkyl or
alkenyl group containing 10 to 24 carbon atoms and R.sup.b represents
hydrogen, an alkyl group with 1 to 4 carbon atoms, or a CH.sub.2 COOH
group, or an acid anhydride, acid chloride or ester thereof, and (d) a di-
or polycarboxylic acid containing from 36 to 100 carbon atoms or an acid
anhydride, acid chloride or ester thereof, at least one of the surfactants
being a sulphurized or non-sulphurized phenol and the other, or at least
one other, of the surfactants being a surfactant other than a phenol
surfactant, the proportion of the said phenol is the surfactant system
being at least 35 mass %, and the overbased detergent having a TBN:%
surfactant ratio of at least 15;
(5) a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants other than (c) an acid of the formula
R.sup.a --CH(R.sup.b)--COOH, wherein R.sup.a represents an alkyl or
alkenyl group containing 10 to 24 carbon atoms and R.sup.b represents
hydrogen, an alkyl group with 1 to 4 carbon atoms, or a CH.sub.2 COOH
group, or an acid anhydride, acid chloride or ester thereof, and (d) a di-
or polycarboxylic acid containing from 36 to 100 carbon atoms or an acid
anhydride, acid chloride or ester thereof, at least one of the surfactants
being a sulphurized or non-sulphurized salicylic acid and the other, or at
least one other, of the surfactants being a surfactant other than a
salicylic surfactant, the proportion of the said salicylic acid in the
surfactant system being at least 10 mass %, and thee overbased detergent
having a TBN:% surfactant ratio of at least 11;
(6) a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants, at least one of the surfactants being a
sulphurized or non-sulphurized phenol and the other, or at least one
other, of the surfactants being a sulphurized or non-sulphurized salicylic
acid, the total proportion of the said phenol and the said salicylic acid
in the surfactant system being at least 55 mass %, and the overbased
detergent having a TBN:% surfactant ratio of at least 11; and
(7) a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants, at least one of which is a sulphurized or
non-sulphurized phenol and the other, or at least one other, of which is a
surfactant other than a phenol surfactant, the proportion of the said
phenol in the surfactant system being at least 15 mass %, and the
overbased detergent having a TBN:% surfactant ratio of at least 21.
21. An additive concentrate as claimed in claim 18 that is substantially
magnesium-free.
Description
This invention relates to compositions suitable for use, inter alia, as
lubricants, to compositions suitable, inter alia, as lubricant additives,
and more especially to compositions comprising calcium overbased
detergents, and to their use in lubricants.
In an internal combustion engine, acidic by-products from the combustion
chamber mix with the lubricating oil and additives are provided in the oil
to neutralize such acids and thereby reduce corrosion. Examples of such
additives are overbased phenates, sulphonates, and salicylates of a number
of metals, e.g., calcium and magnesium.
A typical crankcase lubricant will contain a number of such detergents, for
example calcium sulphonate, calcium phenate, and magnesium sulphonate.
In earlier years, overbased materials contained only a single type of
anion, but more recently compositions have been available that contain
anions of two or more types, obtained either by mixing together two or
more overbased materials having different types of anion or by the
manufacture of a material in which two or more anions of different types
are incorporated during overbasing, the last-mentioned materials being
known as "hybrid" or "complex" detergents. Complex materials have the
advantages that they contribute the properties given by two or more
surfactants without the need to manufacture and blend separate materials,
and that the problems of instability or incompatibility associated with
separate materials are avoided.
In our co-pending International Applications Nos. EP97/02695, 02696, 02697,
02698, and 02699, (Published as WO 97/46645, 97/46643, 97/46644, 97/46646
and 97/146647) the disclosures of all of which are incorporated herein by
reference, are described a number of such complex detergents, and
processes for their manufacture, the detergents having a relatively high
ratio of total base number (hereinafter TBN, measured in mg KOH/g
according to ASTM D2896) to surfactant. These materials, because they
combine high basicity with a relatively low surfactant content, provide an
economic advantage.
The ratio of TBN to surfactant may be determined as described in any one of
the above-mentioned international applications. These give details of how
the percentage of total surfactant in a detergent is, and the proportions
of individual surfactants are, measured. For convenience, these procedures
are summarized in an Appendix below. The term "TBN:% surfactant ratio" as
used in this specification, including the claims, is defined as the ratio
of the TBN to the percentage of total surfactant in the detergent measured
as described in the above-mentioned International applications and in the
Appendix below.
As used herein, by the term "calcium detergent" is meant a detergent in
which at least 80 mole %, typically at least 90 mole % and more especially
at least 95 mole % of the cations are calcium.
It has surprisingly been found that by replacing some or all of one or more
single anion detergents in a lubricant composition by a complex one,
advantageously one described in one of the above-mentioned International
applications, the same protection against corrosion may be obtained at a
lower TBN or a greater protection may be obtained at the same TBN.
The multifunctional complex detergent facilitates enhanced performance in
corrosion protection and deposit control at least when both sulphonate and
phenate are present.
The present invention accordingly provides in a first aspect a lubricating
oil composition comprising a mixture of at least two metal-containing
detergents, a first, detergent (a), being a metal phenate, sulphonate,
salicylate, naphthenate, or carboxylate, and a second, detergent (b),
being a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants, at least one of which is a sulphurized or
non-sulphurized phenol or a derivative thereof and the other, or at least
one other, of which is a surfactant other than a phenol surfactant, the
proportion, measured as described herein, of the said phenol in the
surfactant system being at least 45 mass %, and the overbased detergent
having a TBN:% surfactant ratio (as hereinbefore defined) of at least 14,
advantageously at least 15, especially at least 19.
The present invention also provides in a second aspect a lubricating oil
composition comprising a mixture of at least two metal-containing
detergents, a first, detergent (a), being a metal phenate, sulphonate,
salicylate, naphthenate, or carboxylate, and a second, detergent (b),
being a calcium overbased detergent comprising a surfactant system derived
from at least surfactants, at least one of which is sulphurized or
nonsulphurized salicylic acid or a derivative thereof and the other, or at
least one other, of which is a surfactant other than a salicylic
surfactant, the proportion, measured as described herein, of the said
salicylic acid in the surfactant system being at least 25 mass %, and the
overbased detergent having a TBN:% surfactant ratio (as hereinbefore
defined) of at least 16.
The present invention further provides in a third aspect a lubricating oil
composition comprising a mixture of at least two metal-containing
detergents, a first, detergent (a), being a metal phenate, sulphonate,
salicylate, naphthenate, or carboxylate, and a second, detergent (b),
being a calcium overbased detergent comprising a surfactant system derived
from at least three surfactants, at least one of the surfactants being a
sulphurized or non-sulphurized phenol or a derivative thereof, at least
one other of the surfactants being a sulphurized or non-sulphurized
salicylic acid or a derivative thereof, the third, or a third, surfactant
being a surfactant other than a phenol or salicylic surfactant, the
proportion, measured as described herein, of the said phenol in the
surfactant system being at least 35 mass %, and the overbased detergent
having a TBN:% surfactant ratio (as hereinbefore defined) of at least 11,
preferably at least 12.
The present invention further provides in a fourth aspect a lubricating oil
composition comprising a mixture of at least two metal-containing
detergents, a first, detergent (a), being a metal phenate, sulphonate,
salicylate, naphthenate, or carboxylate, and a second, detergent (b),
being a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants other than (c) an acid of the formula
R.sup.a --CH(R.sup.b)--COOH, wherein R.sup.a represents an alkyl or
alkenyl group containing 10 to 24 carbon atoms and R.sup.b represents
hydrogen, an alkyl group with 1 to 4 carbon atoms, or a CH.sub.2 COOH
group, or an acid anhydride, acid chloride or ester thereof, and (d) a di-
or polycarboxylic acid containing from 36 to 100 carbon atoms or an acid
anhydride, acid chloride or ester thereof, at least one of the surfactants
being a sulphurized or non-sulphurized phenol or a derivative thereof and
the other, or at least one other, of the surfactants being a surfactant
other than a phenol surfactant, the proportion, measured as described
herein, of the said phenol in the surfactant system being at least 35 mass
%, and the overbased detergent having a TBN:% surfactant ratio (as
hereinbefore defined) of at least 15.
The present invention further provides in a fifth aspect a lubricating oil
composition comprising a mixture of at least two metal-containing
detergents, a first, detergent (a), being a metal phenate, sulphonate,
salicylate, naphthenate, or carboxylate, and a second, detergent (b),
being a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants other than (c) an acid of the formula
R.sup.a --CH(R.sup.b)--COOH, wherein R.sup.a represents an alkyl or
alkenyl group containing 10 to 24 carbon atoms and R.sup.b represents
hydrogen, an alkyl group with 1 to 4 carbon atoms, or a CH.sub.2 COOH
group, or an acid anhydride, acid chloride or ester thereof, and (d) a di-
or polycarboxylic acid containing from 36 to 100 carbon atoms or an acid
anhydride, acid chloride or ester thereof, at least one of the surfactants
being a sulphurized or non-sulphurized salicylic acid or a derivative
thereof and the other, or at least one other, of the surfactants being a
surfactant other than a salicylic surfactant, the proportion, measured as
described herein, of the said salicylic acid in the surfactant system
being at least 10 mass %, and the overbased detergent having a TBN:%
surfactant ratio (as hereinbefore defined) of at least 11.
The present invention further provides in a sixth aspect a lubricating oil
composition comprising a mixture of at least two metal-containing
detergents, a first, detergent (a), being a metal phenate, sulphonate,
salicylate, naphthenate, or carboxylate, and a second, detergent (b),
being a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants, at least one of the surfactants being a
sulphurized or non-sulphurized phenol or a derivative thereof and the
other, or at least one other, of the surfactants being a sulphurized or
non-sulphurized salicylic acid or a derivative thereof, the total
proportion, measured as described herein, of the said phenol and the said
salicylic acid in the surfactant system being at least 55 mass %, and the
overbased detergent having a TBN:% surfactant ratio (as hereinbefore
defined) of at least 11, preferably at least 13.
Advantageously, in the sixth aspect, when the ratio is less than 13, the
total proportion of the phenol and the salicylic acid is at least 65 mass
%.
The present invention further provides in a seventh aspect a lubricating
oil composition comprising a mixture of at least two metal-containing
detergents, a first, detergent (a), being a metal phenate, sulphonate,
salicylate, naphthenate, or carboxylate, and a second, detergent (b),
being a calcium overbased detergent comprising a surfactant system derived
from at least two surfactants, at least one of which is a sulphurized or
non-sulphurized phenol or a derivative thereof and the other, or at least
one other, of which is a surfactant other than a phenol surfactant, the
proportion, measured as described herein, of the said phenol in the
surfactant system being at least 15 mass %, and the overbased detergent
having a TBN:% surfactant ratio (as hereinbefore defined) of at least 21.
In addition to the advantage mentioned above, a composition of the
invention gives, in certain circumstances, another important advantage,
that of reduced wear. In order to pass the Sequence IID corrosion test,
described below, at an acceptable cost, it has frequently been necessary
to include an overbased magnesium sulphonate in the composition. It has
been found, however, that magnesium overbased detergents cause more wear
than calcium overbased detergents and therefore require a higher level of
anti-wear agent in the composition. The replacement of some or all
magnesium sulphonate by detergent (b) allows a lower proportion of
anti-wear agent to be used, thereby further reducing cost.
Advantageously, therefore, the composition of the invention is
substantially magnesium-free.
The invention also provides an additive concentrate comprising detergents
(a) and (b) as defined above in an oil, or a solvent or dispersant
miscible with oil, the total proportion of detergent in the concentrate
being from 2.5 to 90, advantageously from 5 to 75, and preferably from 8
to 60, mass %.
As examples of the detergent (a) there may be mentioned neutral and
overbased phenates, salicylates, and sulphonates, advantageously of Group
1 and Group 2 metals of the Periodic Table, especially calcium and
magnesium. The anions of detergent (a) materials are from a single group,
e.g., are phenol-derived, or sulphonic acid-derived, but it is within the
scope of the invention to employ a mixture of anions within a single
group. For example, when a sulphurized phenol surfactant is used and has
been prepared by the reaction of elemental sulphur and a phenol, the
number of sulphur atoms bridging the phenolic moieties will vary, as may
the number of phenolic moieties linked by sulphur. The reader is referred
to the above-mentioned International Applications for examples of anions
suitable for use in detergent (a), including those of sulphurized and
non-sulphurized phenols, aldehyde-modified phenols, Mannich-base condensed
phenols, sulphurized and non-sulphurized salicylic acids, sulphonic acids,
carboxylic acids and naphthenic acids.
As examples of preferred detergent (a), there may be mentioned calcium
sulphonates having a TBN of at least 50, especially from 350 to 450, more
especially about 400, calcium phenates having a TBN of up to 160, calcium
salicylates having a TBN up to 100, and calcium sulphonates having a TBN
of up to 50.
As examples of detergent (b), there may be mentioned all those hybrid or
complex detergents described in the above-mentioned International
Applications. Advantageously, in the first aspect, the proportion of the
phenol in the surfactant system of detergent (b) is at least 55 mole %.
Advantageously, the phenol if present is hydrocarbyl, preferably alkyl,
substituted. Advantageously, one of the surfactants from which detergent
(b) is derived is a sulphonic acid (or derivative), advantageously a
hydrocarbyl, preferably alkyl, substituted aryl sulphonic acid. As a
preferred example, there may be mentioned a calcium phenatelsulphonate of
mass ratio about 50:50, having a standardized TBN of 385 and a TBN:%
surfactant ratio of 20.
The detergent (b) is advantageously made by the process described in WO
97/46646.
It is within the scope of the invention to use two or more simple
detergents, detergents (a); it is also within the scope of the invention
to use two or more complex detergents, detergents (b). In a preferred
embodiment, the composition comprises at least one simple overbased
calcium phenate, at least one simple calcium overbased sulphonate, and at
least one complex calcium overbased sulphonate; advantageously at least
one simple detergent is, and preferably at least two are, of low TBN (at
most 160 in the case of phenate and at most 50 in the case of sulphonate).
Advantageously the simple detergent(s):complex detergent mass ratio is from
1:5 to 5:1, preferably from 1:3 to 3:1, and more preferably from 2:3 to
3:2.
Advantageously, the total proportion of the two detergents (a) and (b) in a
lubricating oil composition according to the invention is within the range
of from 0.25 to 3, preferably 0.5 to 1.5, and more preferably 0.75 to
1.25, mass per cent, of active ingredient.
The detergents may be incorporated into a base oil in any convenient way.
They may be added directly to the oil by dispersing or by dissolving them
in the oil at the desired level of concentration, optionally with the aid
of a suitable solvent such, for example, as toluene or cyclohexane. Such
blending can occur at room temperature or at elevated temperature.
Detergent compositions according to, or prepared in accordance with, the
invention are particularly useful in lubricating oil compositions which
employ a base oil in which the mixtures are dissolved or dispersed. Base
oils with which the detergent compositions may be used are especially
those suitable for use as crankcase lubricating oils for spark-ignited and
compression-ignited internal combustion engines, for example, automobile
and truck engines.
Synthetic base oils include alkyl esters of dicarboxylic acids, polyglycols
and alcohols; poly-.alpha.-olefins, including polybutenes; alkyl benzenes;
organic esters of phosphoric acids; and polysilicone oils.
Natural base oils include mineral lubricating oils which may vary widely as
to their crude source, for example, as to whether they are paraffinic,
naphthenic, mixed, or paraffinic-naphthenic, as well as to the method used
in their production, for example, their distillation range and whether
they are straight run or cracked, hydrofined, or solvent extracted.
Lubricating oil base stocks suitable for use in crankcase lubricants
conveniently have a viscosity of 2.5 to 12 cSt, (mm.sup.2 /s), at
100.degree. C., although base stocks with other viscosities may be used,
for example, bright stock.
The lubricating oil composition in accordance with the present invention
comprises lubricating oil, typically in a major proportion, and the
detergents (a) and (b), typically in a minor proportion.
Advantageously, detergent (a) is present in a proportion within the range
of from 0.005 to 2.5, preferably from 0.05 to 1.5, and most preferably
from 0.25 to 1, mass %, based on the total mass of lubricant composition.
Advantageously, detergent (b) is present in a proportion within the range
of from 0.005 to 1.5, preferably from 0.05 to 1.25, and most preferably
from 0.25 to 0.75, mass %, based on the total mass of lubricant
composition.
Additional additives may be incorporated in the composition to enable it to
meet particular requirements. Examples of additional additives which may
be included in lubricating oil compositions containing a detergent
composition in accordance with the invention are viscosity index
improvers, corrosion inhibitors, oxidation inhibitors or antioxidants,
friction modifiers, dispersants, other detergents, metal rust inhibitors,
anti-wear agents, pour point depressants, and antifoaming agents.
Viscosity index improvers (or viscosity modifiers) impart high and low
temperature operability to a lubricating oil and permit it to remain shear
stable at elevated temperatures and also exhibit acceptable viscosity or
fluidity at low temperatures.
Suitable compounds for use as viscosity modifiers are generally high
molecular weight hydrocarbon polymers, including polyesters, and viscosity
index improver dispersants, which function as dispersants as well as
viscosity index improvers. Oil-soluble viscosity modifying polymers
generally have weight average molecular weights of from about 10,000 to
1,000,000, preferably 20,000 to 500,000, as determined by gel permeation
chromatography or light scattering methods.
Corrosion inhibitors reduce the degradation of metallic parts contacted by
the lubricating oil composition. Thiadiazoles, for example those disclosed
in U.S. Pat. No. 2, 719,125, 2,719,126 and 3,087,932, are examples of
corrosion inhibitors for lubricating oils.
Oxidation inhibitors, or antioxidants, reduce the tendency of mineral oils
to deteriorate in service, evidence of such deterioration being, for
example, the production of varnish-like deposits on metal surfaces and of
sludge, and viscosity increase. Suitable oxidation inhibitors include
sulphurized alkyl phenols and alkali or alkaline earth metal salts
thereof; diphenylamines; phenyl-naphthylamines; and phosphosulphurized or
sulphurized hydrocarbons.
Other oxidation inhibitors or antioxidants which may be used in lubricating
oil compositions comprise oil-soluble copper compounds. The copper may be
blended into the oil as any suitable oil-soluble copper compound. By
oil-soluble it is meant that the compound is oil-soluble under normal
blending conditions in the oil or additive package. The copper may, for
example, be in the form of a copper dihydrocarbyl thio- or
dithio-phosphate. Alternatively, the copper may be added as the copper
salt of a synthetic or natural carboxylic acid, for example, a C.sub.8 to
C.sub.18 fatty acid, an unsaturated acid, or a branched carboxylic acid.
Also useful are oil-soluble copper dithiocarbamates, sulphonates,
phenates, and acetylacetonates. Examples of particularly useful copper
compounds are basic, neutral or acidic copper Cu.sup.l and/or Cu.sup.II
salts derived from alkenyl succinic acids or anhydrides.
Friction modifiers and fuel economy agents which are compatible with the
other ingredients of the final oil may also be included. Examples of such
materials are glyceryl monoesters of higher fatty acids, esters of long
chain polycarboxylic acids with diols, and oxazoline compounds, and
oil-soluble molybdenum compounds.
Dispersants maintain oil-insoluble substances, resulting from oxidation
during use, in suspension in the fluid, thus preventing sludge
flocculation and precipitation or deposition on metal parts. So-called
ashless dispersants are organic materials which form substantially no ash
on combustion, in contrast to metal-containing (and thus ash-forming)
detergents. Borated metal-free dispersants are also regarded herein as
ashless dispersants. Suitable dispersants include, for example,
derivatives of long chain hydrocarbon-substituted carboxylic acids in
which the hydrocarbon groups contain 50 to 400 carbon atoms, examples of
such derivatives being derivatives of high molecular weight
hydrocarbyl-substituted succinic acid. Such hydrocarbyl-substituted
carboxylic acids may be reacted with, for example, a nitrogen-containing
compound, advantageously a polyalkylene polyamine, or with an ester.
Particularly preferred dispersants are the reaction products of
polyalkylene amines with alkenyl succinic anhydrides.
A viscosity index improver dispersant functions both as a viscosity index
improver and as a dispersant. Examples of viscosity index improver
dispersants suitable for use in lubricating compositions include reaction
products of amines, for example polyamines, with a hydrocarbyl-substituted
mono- or dicarboxylic acid in which the hydrocarbyl substituent comprises
a chain of sufficient length to impart viscosity index improving
properties to the compounds.
Examples of dispersants and viscosity index improver dispersants may be
found in EP-A-24146.
Additional detergents and metal rust inhibitors include the metal salts,
which may be overbased, of sulphonic acids, alkyl phenols, sulphurized
alkyl phenols, alkyl salicylic acids, thiophosphonic acids, naphthenic
acids, and other oil-soluble mono- and dicarboxylic acids. Representative
examples of detergents/rust inhibitors, and their methods of preparation,
are given in EP-A-208 560.
Antiwear agents, as their name implies, reduce wear of metal parts. Zinc
dihydrocarbyl dithiophosphates (ZDDPs) are very widely used as antiwear
agents. Especially preferred ZDDPs for use in oil-based compositions are
those of the formula Zn[SP(S)(OR.sup.1)(OR)].sub.2 wherein R.sup.1 and
R.sup.2 represent alkyl groups, each containing from 1 to 18, and
preferably 2 to 12, carbon atoms.
Pour point depressants, otherwise known as lube oil flow improvers, lower
the minimum temperature at which the fluid will flow or can be poured.
Such additives are well known. Foam control may be provided by an
antifoamant of the polysiloxane type, for example, silicone oil or
polydimethyl siloxane.
Some of the above-mentioned additives may provide a multiplicity of
effects; thus for example, a single additive may act as a
dispersant-oxidation inhibitor. This approach is well known and need not
be further elaborated herein.
When lubricating compositions contain one or more of the above-mentioned
additives, each additive is typically blended into the base oil in an
amount which enables the additive to provide its desired function.
Representative effective amounts of such additives, when used in crankcase
lubricants, are as follows:
______________________________________
Mass % a.i.
Mass % a.i.
Additive (Broad) (Preferred)
______________________________________
Viscosity Modifier
0.01-6 0.01-4
Corrosion Inhibitor
0.01-5 0.01-1.5
oxidation Inhibitor
0.01-5 0.01-1.5
Friction Modifier 0.01-5 0.01-1.5
Dispersant 0.1-20 0.1-8
Detergents/rust inhibitors
0.01-6 0.01-3
Anti-wear Agent 0.01-6 0.01-4
Pour Point Depressant
0.01-5 0.01-1.5
Anti-Foaming Agent
0.001-3 0.001-0.15
Mineral or Synthetic Base Oil
Balance Balance
______________________________________
* Mass % active ingredient based on the final oil.
It will be understood that the various components of the composition, the
essential components as well as the optional and customary components, may
react under the conditions of formulation, storage, or use, and that the
invention also provides the product obtainable or obtained as a result of
any such reaction.
The following examples, in which all parts and percentages are by weight
unless indicated otherwise, illustrate the invention.
The Sequence IID and VW Intercooled Turbodiesel tests are carried out in
accordance with ASTM STP 315 H and CEC L-46 T-63 procedures, respectively.
Example A (Comparative)
In this example various samples of a commercially available heavy duty
lubricating oil were subjected to the above-mentioned Sequence IID test.
The composition of the oils, with an average TBN of 9.01, was as follows:
______________________________________
Mass per cent
Magnesium sulphonate, TBN 400
0.25
Calcium sulphonate, TBN 300
0.55
Calcium sulphonate, TBN 27
0.45
Calcium phenate, TBN 135
0.45
Additives for other functions
8.00
Base Oil (Solvent Neutral 175)
balance.
Average test results were as follows:
Merits
Lifter Bodies 8.63
Plungers 8.67
Balls 8.60
Relief Valve Plunger 8.00
Pushrods 8.78
Severity Adjustment 0.00
Average Rust 8.56
Pass/Fail pass
______________________________________
Examples 1 to 4
In these examples, a complex calcium phenate/sulphonate, 50:50 mass
phenate: sulphonate ratio, TBN 385, TBN:% surfactant ratio 20:1, referred
to below as the complex detergent, wholly or partly replaced various of
the detergents of the reference composition. The composition and the
results of the Sequence IID results are given below:
______________________________________
Example No. 1 2 3 4
______________________________________
Magnesium sulphonate, TBN 400
-- -- -- --
Calcium sulphonate, TBN 300
-- -- -- --
Calcium sulphonate, TBN 27
0.45 0.45 0.45 0.45
Calcium phenate, TBN 135
-- -- 0.23 0.23
Complex detergent
1.12 0.70 0.55 0.40
Oil, Additives for other purposes
Balance
TBN of oil 11.64 8.23 7.61 6.38
Test Results, Merits
Lifter Bodies 8.84 8.84 8.72 8.34
Plungers 8.76 8.77 8.81 8.81
Balls 8.60 8.45 8.56 8.68
Relief Valve Plunger
8.24 8.06 8.05 8.40
Pushrods 8.86 8.83 8.84 8.80
Severity Adjustment
0 0 0 -0.08
Average Rust 8.66 8.59 8.62 8.54
Pass/Fail Pass Pass Pass Pass
______________________________________
The results show that magnesium-based detergent may be replaced by a
complex calcium detergent while still passing the IID Sequencing test,
with the potential for reducing the cost of anti-wear agents. The results
also show that the combination of a lower proportion of a simple calcium
phenate with a complex detergent gives comparable corrosion protection at
a lower total TBN.
Examples B (Comparative) and 5 to 8
In these Examples, lubricating oil compositions according to the invention
were compared with a commercially available heavy duty lubricating oil in
the VW Intercooled Diesel test, a measure of deposit control. The complex
calcium detergent (b) was incorporated in the oil at a constant level, and
the simple detergents in the commercial oil replaced on different bases;
in Example 5 on an equi-sulphonate and equi-phenate basis; in Example 6 at
an approximately equal TBN, and in Example 7 at equi-phenate only. In
Example 8, also run on an equiphenate basis, a different nonyl phenyl
sulphide (NPS) was used, one derived from a lower chlorine content source.
It is believed that the failure of Example 7 in the test, caused by a
pinched piston ring, was an isolated failure, and not due to the absence
of the high TBN magnesium sulphonate. The compositions and results are
shown below.
______________________________________
B 5 6 7 8
______________________________________
Magnesium sulphonate, TBN 400
0.25 -- -- -- --
Calcium sulphonate, TBN 300
0.8 0.8 -- -- --
Calcium sulphonate, TBN 27
0.45 0.45 0.45 0.45 0.45
Calcium phenate, TBN 135
0.5 0.28 0.5 0.28 0.28
Complex detergent
-- 0.55 0.55 0.55 0.55
TBN 9.1 12.5 8.3 7.7 7.7
% Phenate 0.47 0.47 0.68 0.47 0.47
% Sulphonate 1.1 1.1 0.8 0.8 0.8
Oil, additives for other purposes
Balance
Merits 7.4 7.4 72 7.4 7.3
Pinched Rings 0 0 0 1 0
Pass/Fail Pass Pass Pass Fail Pass
______________________________________
The compositions according to the invention provide the necessary deposit
control, while avoiding the need for a magnesium-based detergent, thus
allowing a lower antiwear agent level. Further, the lower TBN of Examples
6 to 8 represents a desirably lower ash content.
The use of the complex detergent also makes it possible to use a lower
treat rate of low base number calcium phenate.
The complex detergent used in Examples 1 to 8 above was made according to
the procedure described below.
Toluene (540 g), methanol (276 g) and diluent oil (150N) (22 g) were
introduced into a reactor and mixed while maintaining the temperature at
approximately 20.degree. C. Calcium hydroxide (Ca(OH).sub.2) (145 g) was
added, and the mixture was heated to 40.degree. C., with stirring. To the
slurry obtained in this way was added a mixture, maintained at 40.degree.
C. of the phenol (230 g) and of the sulphonic acid (110 g) surfactants
identified below and toluene (100 g), followed by a further quantity (50
g) of toluene, and water (22 g).
After neutralization of the surfactants by the calcium hydroxide, the
temperature of the mixture was reduced to approximately 28.degree. C. and
was maintained at approximately 28.degree. C. while carbon dioxide (62 g)
was injected into the mixture at a rate such that substantially all the
carbon dioxide was absorbed in the reaction mixture to form the basic
material. The temperature was then raised to 60.degree. C. over 60
minutes, following which the mixture was cooled to a temperature of
approximately 28.degree. C. over 30 minutes. At 28.degree. C., a further
quantity of calcium hydroxide (124 g) was added and carbon dioxide (62 g)
was charged. After this second carbonation step, the temperature was
raised to 60.degree. C. over 90 minutes.
Subsequently, the volatile materials were distilled off, a second charge of
diluent oil (243 g) was introduced, and the product was filtered to remove
sediment. The product had a TBN of 385, and a TBN:% surfactant ratio of
about 20.
The phenol surfactant was a sulphurized alkyl phenol, obtained from sulphur
monochloride and a blend of tertiary nonyl phenols (predominantly para)
and di(tertiary nonyl) phenols (predominantly ortho and para). The
sulphonic acid surfactant was an alkylbenzene sulphonic acid, molecular
weight 683. Although the surfactants were applied at an approximately 2:1
mass ratio, a lower proportion of the phenol than of the sulphonate reacts
with calcium, and the final calcium detergent has an approximately 50:50
mass ratio of phenate: sulphonate.
Appendix
The percentage of surfactant in the complex detergent, and the percentages
of the individual surfactants, for example, the phenol, in the surfactant
system, are the percentages measured by the methods set out below.
1. Dialysis of the overbased detergent
A known amount (A g, approximately 20 g) of the liquid complex overbased
detergent (substantially free from other lubricating oil additives) is
dialysed through a membrane in a Soxhlet extractor (150 mm height.times.75
mm internal diameter) using n-hexane siphoning at a rate of 3 to 4 times
per hour for 20 hours. The membrane should be one which retains
substantially all the metal containing material and passes substantially
all the remainder of the sample. An example of a suitable membrane is a
gum rubber membrane supplied by Carters Products, Division of Carter
Wallace Inc., New York, N.Y. 10105 under the trade name Trojans. The
dialysate and residue obtained on completion of the dialysis step are
evaporated to dryness, any remaining volatile material then being removed
in a vacuum oven (100.degree. C. at less than 1 torr or less than about
130 Pa). The mass of the dried residue, in grams, is designated B. The
percentage (C) of overbased detergent material in the liquid sample is
given by the equation:
##EQU1##
Background information for the dialysis technique is given by Amos, R. and
Albaugh, E. W. in "Chromatography in Petroleum Analysis", Altgelt, K. H.
and Gouw, T. H., Eds, pages 417 to 422, Marcel Dekker, Inc., New York and
Basel, 1979.
2. Determination of TBN:% total surfactant ratio
A known amount (D g, approximately 10 g) of the dried residue is hydrolysed
as specified in sections 8.1 to 8.1.2 of ASTM D3712, except that at least
200 ml of 25% by volume hydrochloric acid (sp. gr. 1.18) is used in
section 8.1.1. The amount of hydrochloric acid used should be sufficient
to effect acidification/hydrolysis of the overbased detergent residue into
organic materials (surfactants) and inorganic materials
(calcium-containing materials, for example, calcium chloride). The
combined ether extracts are dried by passing them through anhydrous sodium
sulphate. The sodium sulphate is rinsed with clean ether, and the combined
ether solutions are evaporated to dryness (at approximately 110.degree.
C.) to yield a hydrolysed residue. The mass of the dried hydrolysed
residue, in grams, is designated E.
The percentage, Y, of total surfactants in the original liquid overbased
detergent is given by the equation:
##EQU2##
and the TBN:% total surfactant ratio, X, is given by the equation:
##EQU3##
It will be noted that, in determining X, the mass of the surfactants in
their free form (that is, not in the form of a salt or other derivative)
is used.
3. Determination of individual surfactants (in their free form) in the
surfactant system
The techniques described below isolate the individual surfactants, in
hydrolysed form, from the hydrolysed surfactant mixture derived from the
overbased detergent. As indicated below, the proportion of each individual
surfactant is the proportion by mass of the individual surfactant, in
hydrolysed form, in the hydrolysed surfactant mixture. Thus, where, for
example, the overbased detergent contains a calcium
phenate/sulphonate/salicylate surfactant system, the proportions of the
individual surfactants in the surfactant system are expressed as the
proportions of phenol, sulphonic acid and salicylic acid respectively.
The proportions of individual surfactants may be determined by the
following method.
A known amount (F g, approximately 1 g) of the dried hydrolysed residue
obtained as described above is placed at the top of a 450.times.25 mm
(internal diameter) fritted glass column filled with 60-100 US mesh (150
to 250 .mu.m) Florisil. Florisil is magnesium silicate with a CAS number
of 8014-97-9. The column is eluted with a 250 ml portion of each of seven
solvents of increasing polarity, namely, heptane, cyclohexane, toluene,
ethyl ether, acetone, methanol, and, lastly, a mixture of 50 volume %
chloroform, 44 volume % isopropanol, and 6 volume % ammonia solution (sp.
gr. 0.88). Each fraction is collected, evaporated to dryness, and the
resulting residue is weighed and then analysed to determine the amount
(G.sup.1, G.sup.2, G.sup.3. . . g) and nature of the surfactant(s)
contained in the fraction.
Analysis of the fractions (or of the hydrolysed residue) can be carried out
by, for example, chromatographic, spectroscopic, and/or titration (colour
indicator or potentiometric) techniques known to those skilled in the art.
Where the overbased detergent contains a sulphonate surfactant and a
salicylate surfactant, the sulphonic acid and salicylic acid obtained by
hydrolysis of these surfactants will usually be eluted from the column
together. In this case, and in any other case where it is necessary to
determine the proportion of sulphonic acid in a mixture containing it, the
proportion of sulphonic acid in the mixture may be determined as described
by Epton in Trans.Far.Soc. April 1948, 226.
In the above method, the mass (in grams, designated H') of a given
surfactant, in hydrolysed form, is determined from the fractions)
containing it, and thus the proportion of that surfactant in the
surfactant system of the original overbased detergent is
##EQU4##
The percentages (by mass) of the individual surfactants (in their free
form, that is, not in the form of a salt or other derivative) based on the
surfactant system may be predicted from the proportions of the surfactants
used as starting materials, provided that the percentage of "reactive
ingredient" (i.e., the percentage of starting material that reacts with
calcium and does not remain in unreacted, non-salt, form in the liquid
detergent) is known for each of the surfactant starting materials. The
percentage of the total surfactants (in their free form) in the liquid
overbased product may then be predicted, and the TBN:% surfactant ratio
determined.
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